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Re: How Did Hadrosaurs Survive? (Was: Hadrosaur "mummy" questions)



Jordan Mallon wrote:
> 
> I sort of liked that idea myself, until HP Brett Booth (or was it his wife?)
> brought up an interesting argument a couple of months ago.  Unless chasing
> prey into the mounths of the larger adults was instinctive, how would the
> young'uns know how to do this if their parents weren't already fast enough
> to teach them?  Many hunting behaviours are learned, and in this case, the
> adult tyrannosaurs would likely have to show their kids the proper
> technique.

Easy. They learn it from their older siblings. Tyrannosaurs didn't reach
full maturity in just one year (not without Proton Energy Pills). If it
took up to ten years or so for a tyrannosaur to reach full adulthood,
then very young chicks could have observed their older siblings from
previous years hunting.

Then again, much of what birds do is instinctive. When young megapodes
hatch, they can already fly. Their parents don't play any role in their
upbringing. They go out on their own immediately, instinctively knowing
how to fly, search for food and avoid predators. When it comes time to
reproduce, they know how to go about that too, perhaps with no direct
observation of others ever having done so. 

My own personal theory on the Lark Quarry footprint site in Queensland
is that it MIGHT represent a single adult theropod taking a creche of
smaller juveniles down to a drying lake to drink. Large animals don't
need to drink as frequently as smaller ones (take desert elephants for
example), so the whole extended theropod family (assuming they weren't
solitary) wouldn't have needed to drink at once. It would only have
taken one adult to act as chaperone for a gaggle of extremely young
animals. 

Alternatively, perhaps some large theropods were solitary, but collected
a creche of juveniles (both theirs and of other adults), much like
caymens and ostriches do.

Once there, the excitable youngsters saw a bunch of small ornithopods,
and chased them about like lunatics while the much wiser adult calmly
stolled along ignoring the little herbivores. Hence why you have the
smaller theropod tracks heading towards the large theropod, with their
tracks sometimes overprinted on the big-un's own prints. In this case,
chasing things would have been instinctive (as it is with many young
predators) even if they had never observed a hunt themselves.

-- 
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Dann Pigdon                   Australian Dinosaurs:
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://www.alphalink.com.au/~dannj/
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